Spike initiation by transmembrane current: a white‐noise analysis.
Spike initiation by transmembrane current: a white‐noise analysis.
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跨膜电流引发尖峰：白噪声分析。
DOI：
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发表时间：
1976
期刊：
影响因子：
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通讯作者：
J. Segundo
中科院分区：
文献类型：
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作者：
H. L. Bryant;J. Segundo
1. 使用高斯白噪声刺激在海兔神经元中检查与尖峰启动相关的跨膜电流的特征。这种刺激的优点在于，它以随机顺序呈现多种波形，而无需预先判断其功效，并且它允许进行简单的统计计算。 2. 用重复的高斯白噪声电流片段进行刺激，显示受测神经元的放电时间具有显着的不变性，并表明它们的反应具有高度的可靠性。 3. 尖峰触发所涉及的频率（小于 5 Hz）忠实地传播长达几毫米，证明了体内电流注射的合理性，以检查触发位点处的尖峰启动。 4. 对尖峰之前的电流波形的检查表明，多种变化都可能是有效的。因此，进行了统计分析，包括计算当前值对的概率密度、平均值、标准差和相关系数。每个统计数据都显示为峰值之前时间的函数。 5. 尖峰之前的平均电流轨迹是多相的，并且取决于直流电的存在和极性。偏见。早期相对较小的向内或向外阶段之后是峰值之前的较大向外阶段。早期阶段倾向于反对直流的极性。偏见。 6. 平均电流轨迹的后期向外阶段在触发动作电位 (AP) 之前达到最大 40‐75 毫秒，并在触发时返回到接近零值。电流峰值出现在 AP 之前的事实可以部分地通过跨膜电流和电势之间的相位延迟来解释。平均电流轨迹未能在峰值后立即返回到控制值，这证明了下降阶段在尖峰触发中的积极作用。 7. 尖峰之前的概率密度呈高斯分布，表明平均值也是最可能的值。尽管密度很宽，证实尖峰之前有各种各样的电流波形，但它们的标准偏差相对于对照显着降低，表明尖峰触发中平均电流轨迹的首选状态。 8. 电流对之间的相关系数矩阵表明，峰值往往先于波形，这些波形部分接近平均电流轨迹，部分保留其形状。 9. 尖峰诱发时期的平均一阶和二阶导数表明，电流斜率和加速度分别在尖峰触发前的最后 200 毫秒内最为关键，并且这些动态刺激成分对于维持在去极化而非超极化偏差下的细胞更为重要。 10...
1. Those features of a transmembrane current correlated with spike initiation were examined in Aplysia neurones using a Gaussian white‐noise stimulus. This stimulus has the advantages that it presents numerous wave forms in random order without prejudgement as to their efficacies, and that it allows straightforward statistical calculations. 2. Stimulation with a repeating segment of Gaussian white‐noise current revealed remarkable invariance in the firing times of the tested neurones and indicated a high degree of reliability of their response. 3. Frequencies (less than 5 Hz) involved in spike triggering propagated faithfully for up to several millimetres, justifying intrasomatic current injection to examine spike initiation at the trigger locus. 4. Examination of current wave forms preceding spikes indicated that a wide variety could be effective. Hence, a statistical analysis was performed, including computation of probability densities, averages, standard deviations and correlation coefficients of pairs of current values. Each statistic was displayed as a function of time before the spike. 5. The average current trajectory preceding a spike was multiphasic and depended on the presence and polarity of a d.c. bias. An early relatively small inward‐ or outward‐going phase was followed by a large outward phase before the spike. The early phase tended to oppose the polarity of the d.c. bias. 6. The late outward phase of the average current trajectory reached a maximum 40‐‐75 msec before triggering the action potential (AP) and returned to near zero values at the moment of triggering. The fact that the current peak occurs in advance of the AP may be partially explained by a phase delay between the transmembrane current and potential. The failure of the average current trajectory to return to control values immediately following the peak argues for a positive role of the declining phase in spike triggering. 7. Probability densities preceding spikes were Gaussian, indicating that the average was also the most probable value. Although the densities were broad, confirming that spikes were preceded by a wide variety of current wave forms, their standard deviations were reduced significantly with respect to controls, suggesting preferred status of the average current trajectory in spike triggering. 8. The matrix of correlation coefficients between current pairs suggested that spikes tended to be preceded by wave forms that in part kept close to the average current trajectory and in part preserved its shape. 9. The average first and second derivatives of spike‐evoking epochs revealed that current slope and acceleration, respectively, were most crucial in the last 200 msec before spike triggering, and that these dynamic stimulus components were more important for a cell maintained under a depolarizing, rather than a hyperpolarizing bias. 10...